First of all, thank you all for your answers.

@Magnus and Thad: it's a bit what I suspected. Since the URL to WorldCat can be rebuilt from the Library of congress authority ID, I guess someone thought it would be a duplicate. 

But 1) I'm not sure that there is a 1 to 1 mapping between all Worldcat Identities and the Library of Congress 2) It would be rather strange that a Library of Congress ID would also serve as an ID for a "competitor" (ie OCLC, which maintains Worldcat and VIAF) 3) One would then wonder why Wikipedia provides both links to the Library of Congress Authority ID and Worldcat Identities.

With respect for the fact that Wikidata already contains links to VIAF and that VIAF contains links to Worldcat Identities, this transitivity reasoning could apply to many other Authority IDs, I think.

@Sebastian: Il would be great! I'll follow this project closely, just as I'm already following your papers. And it is precisely because I know that there is a desire for "rapprochement" on both sides that I asked why there is absolutely nothing in Wikidata that links to DBpedia (or Yago), whereas DBpedia contains a lot of owl: sameAs to Wikidata. All this must have been discussed somewhere I suppose. Still, I do not even find a property proposal for "DBpedia link". 

2018-03-06 18:59 GMT+01:00 Sebastian Hellmann <hellmann@informatik.uni-leipzig.de>:

Hi Ettore,

we just released a very early prototype of the new DBpedia:

http://88.99.242.78/hdt/en_wiki_de_sv_nl_fr-replaced.nt.bz2

I attached the first 1000 triples. The data is a merge of Wikidata + 5  DBpedias from the 5 largest Wikipedia versions. Overall, there are many issues, but we have a test-driven data engineering process combined with Scrum and biweekly releases, next one is on March 15th. The new IDs are also stable by design.

We discussed how to effectively reuse all technologies we have for Wikidata and also Wikipedia and are applying with this project at the moment: https://meta.wikimedia.org/wiki/Grants:Project/DBpedia/GlobalFactSync

(Endorsements on the main page and comments on the talk page are welcome).

We really hope that the project gets accepted, so we can deploy the technologies behind DBpedia to the Wikiverse, e.g. we found over 900k triples/statements with references in the English Wikipedia's Infoboxes alone.

We still have to do documentation and hosting of the new releases, but then it would indeed be a good time to add the links to DBpedia, if nobody objects. Also some people mentioned that we could load the DBpedia Ontology into Wikidata to provide an alternate class hierarchy. In DBpedia we loaded 5 or 6 classification schemes (Yago, Umbel, etc.), which are useful for different kind of queries.

 
All the best,
Sebastian

 

On 06.03.2018 18:14, Ettore RIZZA wrote:

Dear all,

I asked myself a series of questions about the links between Wikidata and other knowledge/data bases, namely those of OCLC and DBpedia. For example:

- Why Wikidata has no property "Worldcat Identities" while the English edition of Wikipedia systematically mentions this identity (when it exists) in its section "Autorithy control"  ? 

- Why do VIAF links to all editions of Wikipedia, but not (simply) to Wikidata ?

- Why is there no link to DBpedia when the opposite is true ?

These questions may seem very different from each other, but they ultimately concern a common subject and are all very basic. I suspect they had to be discussed somewhere, maybe at the dawn of Wikidata. However, I find nothing in the archives of this Newsletter, nor in the discussions on Wikidata. 

Could someone point me to some documentation on these issues ? 

Cheers,

Ettore Rizza

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All the best,
Sebastian Hellmann

Director of Knowledge Integration and Linked Data Technologies (KILT) Competence Center
at the Institute for Applied Informatics (InfAI) at Leipzig University
Executive Director of the DBpedia Association
Projects: http://dbpedia.org, http://nlp2rdf.org, http://linguistics.okfn.org, https://www.w3.org/community/ld4lt
Homepage: http://aksw.org/SebastianHellmann
Research Group: http://aksw.org

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